Allow database source to use different types of joins

lib/etl/control/source/database_source.rb

@@ -28,6 +28,8 @@ class DatabaseSource < Source
       # Other options:
       # * <tt>:join</tt>: Optional join part for the query (ignored unless 
       #   specified)
+      # * <tt>:join_type</tt>: Optional join clause type for a query with a
+      #   join part (defaults to 'JOIN')
       # * <tt>:select</tt>: Optional select part for the query (defaults to 
       #   '*')
       # * <tt>:group</tt>: Optional group by part for the query (ignored 
@@ -62,6 +64,11 @@ def join
         configuration[:join]
       end
 
+      # Get the type of join for the query, defaults to JOIN
+      def join_type
+        configuration[:join_type] || 'JOIN'
+      end
+
       # Get the select part of the query, defaults to '*'
       def select
         configuration[:select] || '*'
@@ -172,7 +179,7 @@ def write_local(file)
       def query
         return @query if @query
         q = "SELECT #{select} FROM #{@table}"
-        q << " JOIN #{join}" if join
+        q << " #{join_type} #{join}" if join
 
         conditions = []
         if new_records_only

test/source_test.rb

@@ -109,6 +109,30 @@ class SourceTest < Test::Unit::TestCase
       @source = ETL::Control::DatabaseSource.new(control, configuration, definition)
     end
 
+    context 'with a join clause' do
+      setup do
+        Person.destroy_all
+        Person.create!( :first_name => 'Bob', :last_name => 'Jones', :ssn => '123456789')
+        Person.create!( :first_name => 'Carol', :last_name => 'Jones')
+        Person.create!( :first_name => 'Bob', :last_name => 'Smith')
+      end
+
+      should 'perform an inner join by default' do
+        size = build_source( :store_locally => true,
+                             :mysqlstream => false,
+                             :join => 'people p2 on p2.last_name = people.last_name and p2.id != people.id').to_a.size
+        assert_equal 2, size
+      end
+
+      should 'allow other types of joins' do
+        size = build_source( :store_locally => true,
+                             :mysqlstream => false,
+                             :join => 'people p2 on p2.last_name = people.last_name and p2.id != people.id',
+                             :join_type => 'left outer join').to_a.size
+        assert_equal 3, size
+      end
+    end
+
     context "with a specified LIMIT `n`" do
       setup do
         ETL::Engine.limit = @limit
@@ -228,4 +252,4 @@ def definition
       }
     ]
   end
-end
+end